There is an apparatus, such as a touch panel, in which a transparent pressure sensor is disposed on a display device displaying an operation screen, and when a user applies a pressure on a button or the like displayed on the operation screen, the pressure sensor detects the pressure and it determines a position where the pressure has been applied.
Examples of position detection methods include a method in which two opposing resistive films of approximately the size of the operation screen are disposed on the display device as a pressure sensor. The two resistive films come into contact with each other at a position where a pressure is applied. By measuring a resistance value of them, the contact position is calculated.